Right now, parts of my design are seen as super thin faces by 3D printing software and Netfabb, making it unprintable. I'd like to be able to combine all of the curves together into one completely solid part, eliminating the super thin faces that seem to be confusing the software, especially the curved faces. So far I've tried Joining the parts, and also extruding them through each other in order to create volume. I guess what I'm wanting to do is the opposite of Shell. I want to add volume and make the part into a complete and total solid.

Hi Bob - a solid is where every edge of every surface is a joined edge between 2 surfaces. When you have any edges that belong only to one surface, that's what is called a "naked edge" and you won't have a solid if you have any naked edges. To identify naked edges you can set up a shortcut key with a script on it as described here:http://moi3d.com/forum/index.php?webtag=MOI&msg=6051.2

When you trigger that shortcut key it will show you all the naked edges in your model , those are the unjoined areas that are preventing things from being a solid. Those spots need to have other surfaces joined together so you've got a joined edge there instead of a naked edge.

You have kind of a long ways to go with this particular model - you've got many surfaces just sticking through each other instead of coming to a common edge, you can't immediately join together something like this which just totally shoots through another piece:

I'm not sure if that's just an extra piece from some previous attempted construction and you just need to delete it, or whether you're trying to incorporate that highlighted surface above into the solid - if you're trying to incorporate it, you've got to Trim all those pieces with each other so that every surface comes to a common edge with another surface, then those surfaces which meet at common edges need to be joined together to make a solid.

Right now you have kind of a whole lot of different surfaces just all sticking through each other and so there is a lot of work you need to do to get them all into a coherent and unified exterior skin before you'll be able to make a solid out of them.

It can be better to try and work with solids at an earlier stage and carve pieces off of a base solid rather than constructing so many different independent surfaces.

I actually did start with solids (attached). Everything seemed fine at that point.

Now, what what weird was that when I did the lofts (second attached) and connected up the "corners" of the part, that's when the issues arose. Before that point in time, the part behaved as one nice, big manipulatable solid. However, the lofting created those lines intersecting the insides of the large semicircles on either side of the part running diagonally, creating what look like triangles. They were not there on the original model - the lofting created them, as odd as that sounds. At that point, the part became unprintable as per Netfabb, the lofting somehow (I'm surmising) pulling or altering the curves that it was based off of.

The main solid (first attached) passed Netfabb and Shapeways before the lofting was attempted. Interestingly, its only when the lofting takes place that the main solid (really, the semicircles and triangular regions) become "stressed" and unprintable, hence my desire to just make the entire thing a solid.

I eliminated those little areas you pointed out on my original attachment to clear things up for clarity.

> I actually did start with solids (attached). Everything seemed fine at that point.

Do you mean your attached file "Remade Funnel 5-1.3dm" ? That does not have just one solid in it, I'm seeing 13 curves, 6 open surfaces, and 8 solids in there...

Here are just the open surfaces being shown - see how many pieces are just sticking right through each other? Those types of areas are not ready to be joined together into a solid:

So maybe I'm completely not understanding what you are asking about, but that file #1 is a long way from being a finished up single solid. If that was accepted as a 3D printable model that's kind of a huge stroke of luck involved, it's not really ready to be printed yet.

To be 3D printed, you've got to have the model configured as just one single solid piece, not a bunch of separate surfaces and many different solids that may be sitting next to each other or sticking partially through each other. In some circumstances it could be possible that could work but if so it's a lucky coincidence and not an expected thing.